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Science · 2022 · 3 marks
CBSE 2022 · Region 2 · Set 1 · Q11
(a) State Ohm's Law. Represent it mathematically. (b) Define 1 ohm. (c) What is the resistance of a conductor through which a current of 0.5 A flows…
(a)
State Ohm's Law. Represent it mathematically.
(b)
Define $\displaystyle 1$ ohm.
(c)
What is the resistance of a conductor through which a current of $\displaystyle 0.5$ A flows when a potential difference of $\displaystyle 2$ V is applied across its ends ?
Marking-scheme solution
(a) The potential difference( \(\displaystyle V\) ) across the ends of a given metallic wire or conductor is directly proportional to the current(I) flowing through it, provided the temperature / physical conditions of the conductor remains the same.
\[\begin{aligned}
& V \propto I \\
& V / I=\text { Constant } \\
& V=I R
\end{aligned}
\]
(b) If the potential difference across the two ends of a conductor is $\displaystyle 1$ V and the current through it is $\displaystyle 1$ A , then the resistance \(\displaystyle R\) of the conductor is $\displaystyle 1$ ohm.
Alternative answer: $\displaystyle 1$ ohm \(\displaystyle =\frac{1 \text { volt }}{1 \text { ampere }}\)
(c)
\(\displaystyle R=\frac{V}{I}\)
\[\mathrm{R}=\frac{2 \mathrm{~V}}{0.5 \mathrm{~A}}
\]
$\displaystyle 4$ ohm
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CBSE Class 10 Science past-paper question from the 2022 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.